Da muss ich dem unsicheren Krieger leider widersprechen:
RAM-Chips sind (und waren) sehr wohl Solid-State.
Lässt sich auch leicht nachlesen, für die jüngeren Semester...
Wikipedia:
A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory...
...
... and SSDs made from RAM can be used for high speed, when data persistence after power loss is not required, or may use battery power to retain data when its usual power source is unavailable.